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Monomeric and self-assembled crystal phases of TNBT

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Rare Metals 2024年第10期43卷 5442-5448页

作者： Yun-Hui Wu Hua-Bei You Wei-Kai Cui Zhi-Qian Cao Xiao Dong Zi-Hui Meng Ming Huang School of Chemistry and Chemical engineering Beijing Institute of Technology Institute of Chemical Materials China Academy of Engineering Physics

（3,3′,5,5′-Tetranitro-4,4′-bi-1,2,4-Triazole） TNBT was designed and predicted more than three decades ago as a high energy *** with many other designed molecules,TNBT has not been successfully synthesized and has not been computationally studied in *** this work,theoretical calculations at density functional theory （DFT）level of theory were carried out for both the gas phase molecule and its possible bulk crystal *** （DFT） computations show that TNBT is comparable to CL-20 with high bulk density,

关键词： Density functional theory

Two innovative equivalent statements of the third law of thermodynamics

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Chinese physics B 2024年第6期33卷 324-328页

作者：陈晓航周颖慧陈金灿 department of physics Xiamen UniversityXiamen 361005China

It is found from textbooks and literature that there are three different statements for the third law of thermodynamics,i.e., the Nernst theorem, the unattainability statement of absolute zero temperature, and the heat capacity statement. It is pointed out that such three statements correspond to three thermodynamic parameters, which are, respectively, the entropy,temperature, and heat capacity, and can be obtained by extrapolating the experimental results of different parameters at ultralow temperatures to absolute zero. It is expounded that because there is no need for additional assumptions in the derivation of the Nernst equation, the Nernst theorem should be renamed as the Nernst statement. Moreover, it is proved that both the Nernst statement and the heat capacity statement are mutually deducible and equivalent, while the unattainability of absolute zero temperature is only a corollary of the Nernst statement or the heat capacity statement so that it is unsuitably referred to as one statement of the third law of thermodynamics. The conclusion is that the Nernst statement and the heat capacity statement are two equivalent statements of the third law of thermodynamics.

关键词： Nernst statement heat capacity statement Nernst theorem absolute zero temperature the third law of thermodynamics

In-Situ Atomic-Scale Observation of Brownmillerite to Ruddlesden-Popper Phase Transition Tuned by Epitaxial Strain in Cobaltites

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Chinese physics Letters 2024年第4期41卷 152-158页

作者：林挺高昂汤哲歆林炜光孙慕华张庆华王雪锋郭尔佳谷林 Beijing National Laboratory for Condensed Matter physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China School of Physical Sciences University of Chinese Academy of ScienceBeijing 100049China Beijing National Center for Electron Microscopy and Laboratory of Advanced Materials Department of Materials Science and EngineeringTsinghua UniversityBeijing 100084China department of physics&Center of Materials Science and Optoelectronics engineering University of Chinese Academy of SciencesBeijing 100049China

Phase transitions involving oxygen ion extraction within the framework of the crystallographic relevance have been widely exploited for sake of superconductivity,ferromagnetism,and ion conductivity in perovskiterelated ***,atomic-scale pathways of phase transitions and ion extraction threshold are inadequately *** we investigate the atomic structure evolution of LaCoO_(3) films upon oxygen extraction and subsequent Co migration,focusing on the key role of epitaxial *** brownmillerite to Ruddlesden-Popper phase transitions are discovered to stabilize at distinct crystal orientations in compressive-and tensile-strained cobaltites,which could be attributed to in-plane and out-of-plane Ruddlesden-Popper stacking faults,respectively.A two-stage process from exterior to interior phase transition is evidenced in compressive-strained LaCoO_(2.5),while a single-step nucleation process leaving bottom layer unchanged in tensile-strained *** analyses reveal that the former process is initiated by an expansion in Co layer at boundary,whereas the latter one is associated with an edge dislocation combined with antiphase *** findings provide a chemomechanical perspective on the structure regulation of perovskite oxides and enrich insights into strain-dependent phase diagram in epitaxial oxides films.

关键词： strained Phase oxides

Analysis of pseudo-random number generators in QMC-SSE method

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Chinese physics B 2024年第3期33卷 75-79页

作者：刘东旭徐维张学锋 department of physics Chongqing UniversityChongqing 401331China

In the quantum Monte Carlo(QMC)method,the pseudo-random number generator(PRNG)plays a crucial role in determining the computation ***,the hidden structure of the PRNG may lead to serious issues such as the breakdown of the Markov ***,we systematically analyze the performance of different PRNGs on the widely used QMC method known as the stochastic series expansion(SSE)*** quantitatively compare them,we introduce a quantity called QMC efficiency that can effectively reflect the efficiency of the *** testing several representative observables of the Heisenberg model in one and two dimensions,we recommend the linear congruential generator as the best choice of *** work not only helps improve the performance of the SSE method but also sheds light on the other Markov-chain-based numerical algorithms.

关键词： stochastic series expansion quantum Monte Carlo pseudo-random number generator

Efficient processed carbon Soot@MoS2 hybrid Bi-functional electrode for dye-sensitized solar cell and asymmetric supercapacitor devices

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Nano Materials Science 2024年第4期6卷 484-494页

作者： B.Arjun Kumar Gopal Ramalingam Salah Addin Burhan Al Omari Zhumabay Bakenov Sambasivam Sangaraju Sangarapani Sudhakar Quantum Material Research Lab (QMRL) Department of Nanoscience and TechnologyAlagappa University department of Mechanical and Aerospace engineering United Arab Emirates University department of Chemical and Materials engineering Nazarbayev University National Water and Energy Center United Arab Emirates University department of physics Alagappa University

A feasible approach to rectify the world's energy demand using sustainable development of adequate energy generation and storage technologies in a single *** this respect,we made a holistic approach with a bifunctional electrode material to perform effectively in energy generation and storage ***2nanosheets were produced by the eco-friendly method and reduced graphene oxide is used to prepared by carbon soot which is derived from castor *** prepared soot and rGO were combined with MoS2nanosheets using a simple sonication *** as-prepared sample was introduced in the supercapacitor and DSSC *** combination MoS2@rGO provides an enhanced conversion efficiency of 11.81%and the reproducibility of DSSC is also ***,MoS2@rGO is used to fabricate an asymmetric supercapacitor to investigate its real-time *** device produced the maximum power density （1666.6 mW/kg） and energy density （25.69 mWh/Kg） at 1 A/*** asymmetric supercapacitor device holds a cyclic stability of 81.4%for 5000 cycles and it powered up an LED device for 4 min.

关键词： Carbon soot Solar cells Supercapacitors MoS 2 DSSC

Effect of distribution shape on the melting transition, local ordering,and dynamics in a model size-polydisperse two-dimensional fluid

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Chinese physics B 2024年第7期33卷 419-428页

作者： Jackson Pame Lenin SShagolsem department of physics National Institute of Technology ManipurImphalIndia

We study the effect of particle size polydispersity(δ) on the melting transition(T*), local ordering, solid–liquid coexistence phase and dynamics of two-dimensional Lennard–Jones fluids up to moderate polydispersity by means of computer simulations. The particle sizes are drawn at random from the Gaussian(G) and uniform(U) distribution *** these systems, we further consider two different kinds of particles, viz., particles having the same mass irrespective of size, and in the other case the mass of the particle scales with its size. It is observed that with increasing polydispersity,the value of T*initially increases due to improved packing efficiency(φ) followed by a decrease and terminates at δ ≈8%(U-system) and 14%(G-system) with no significant difference for both mass types. The interesting observation is that the particular value at which φ drops suddenly coincides with the peak of the heat capacity(CP) curve, indicating a transition. The quantification of local particle ordering through the hexatic order parameter(Q_6), Voronoi construction and pair correlation function reveals that the ordering decreases with increasing δ and T. Furthermore, the solid–liquid coexistence region for the G-system is shown to be comparatively wider in the T –δ plane phase diagram than that for the U system. Finally, the study of dynamics reveals that polydisperse systems relax faster compared to monodisperse systems;however, no significant qualitative differences, depending on the distribution type and mass polydispersity, are observed.

关键词： polydispersity ordering phase diagram dynamics

Ultrahigh-brightness 50 MeV electron beam generation from laser wakefield acceleration in a weakly nonlinear regime

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Matter and Radiation at Extremes 2024年第3期9卷 4-10页

作者： Zhongtao Xiang Changhai Yu Zhiyong Qin Xuhui Jiao Jiahui Cheng Qiaoxuan Zhou Gatie Axi Jianghua Jie Ya Huang Jintan Cai Jiansheng Liu department of physics Shanghai Normal UniversityShanghai 200234China

We propose an efficient scheme to produce ultrahigh-brightness tens of MeV electron beams by designing a density-tailored plasma to induce a wakefield in the weakly nonlinear regime with a moderate laser energy of 120 *** this scheme,the second bucket of the wakefield can have a much lower phase velocity at the steep plasma density down-ramp than the first bucket and can be exploited to implement longitudinal electron injection at a lower laser intensity,leading to the generation of bright electron beams with ultralow emittance together with low energy ***-dimensional particle-in-cell simulations are carried out and demonstrate that high-quality electron beams with a peak energy of 50 MeV,ultralow emittance of28 nm rad,energy spread of 1%,charge of 4.4 pC,and short duration less than 5 fs can be obtained within a 1-mm-long tailored plasma density,resulting in an ultrahigh six-dimensional brightness B6D,n of2×1017 A/m2/0.1%.By changing the density parameters,tunable bright electron beams with peak energies ranging from 5 to 70 MeV,a small emittance of B0.1 mm mrad,and a low energy spread at a few-percent level can be *** bright MeV-class electron beams have a variety of potential applications,for example,as ultrafast electron probes for diffraction and imaging,in laboratory astrophysics,in coherent radiation source generation,and as injectors for GeV particle accelerators.

关键词： weakly nonlinear acceleration

Effect of Eu3+,Bi3+,and Li+ doping on luminescent property of GdNbO4

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Journal of Rare Earths 2024年第1期42卷 66-75页

作者： S.W.Wi Y.S.Lee department of physics and Integrative Institute of Basic Sciences Soongsil University

We investigated the emission properties of Eu3+-doped GdNbO4-based oxide phosphors,aiming at improving the Eu3+emission by codoping of Bi3+and Li+.Eu3+singly doped,Eu3+and Bi3+doubly doped,and Eu3+,Bi3+,and Li+triply doped GdNbO4were prepared using a high-temperature solid-state reaction *** red-orange emissions from Eu3+in the singly doped samples are significantly improved by the codoping of Bi3+,mainly due to the energy transfer from Bi3+to Eu3+.The additional codoping of Li+is found to increase the Eu3+emission *** improvement might be attributed to the increase in the photoluminescent quantum yield originating from larger grain sizes and better crystallinity.A detailed analysis of the X-ray diffraction pattern and the asymmetric ratio estimated from the photoluminescence spectra show that the local lattice environment around Eu3+in GdNbO4does not change significantly with the codoping of Bi3+and Li+.Our results indicate that Li+doping is a promising way to improve the emission properties of rare-earth ion-doped GdNbO4phosphors.

关键词： Eu3+ GdNbO4 Codoping of Li+ Photoluminescence Sensitizer Rare earths

Cascading Failures in Power Grids: A Load Capacity Model with Node Centrality

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Complex System Modeling and Simulation 2024年第1期4卷 1-14页

作者： Chaoyang Chen Yao Hu Xiangyi Meng Jinzhu Yu department of Information and Electrical engineering Hunan University of Science and TechnologyXiangtan 411100China department of physics and Astronomy Northwestern UniversityEvanstonIL 60208USA department of Civil engineering University of TexasArlingtonTX 22201USA

Power grids,due to their lack of network redundancy and structural interdependence,are particularly vulnerable to cascading failures,a phenomenon where a few failed nodes—having their loads exceeding their capacities—can trigger a widespread collapse of all ***,we extend the cascading failure(Motter-Lai)model to a more realistic perspective,where each node’s load capacity is determined to be nonlinearly correlated with the node’s *** analysis encompasses a range of synthetic networks featuring small-world or scale-free properties,as well as real-world network configurations like the IEEE bus systems and the US power *** find that fine-tuning this nonlinear relationship can significantly enhance a network’s robustness against cascading failures when the network nodes are under ***,the selection of initial nodes and the attack strategies also impact overall network *** findings offer valuable insights for improving the safety and resilience of power grids,bringing us closer to understanding cascading failures in a more realistic context.

关键词： load capacity complex network node centrality cascading failures robustness of power grids